Confusing freq_list documentation: does it ever work?

[WGH]

Here's the excerpt from the wpa_supplicant documentation:

    freq_list: Array of allowed frequencies
    Space-separated list of frequencies in MHz to allow for selecting the BSS. If
    set, scan results that do not match any of the specified frequencies are not
    considered when selecting a BSS.

This kinda implies that one can use it to force selection of the 5Ghz band.

However, this doesn't work that way. Jouni Malinen said in 2014[1]:

> freq_list affects only scanning. This does not prevent drivers from
> roaming to other frequencies when BSS-selection is done by the driver
> instead of wpa_supplicant. In other words, this is not a generic
> solution for forcing 5 GHz band to be used.

And, indeed, in my experience, it doesn't affect affect band selection _at all_.

netplan developers were apparently also confused by wpa_supplicant documentation,
as netplan docs are vaguely imply that their "band" settings (which translates
to wpa_supplicant's "freq_list") can be used to to force band selection[2].
I raised an issue on the netplan bug tracker about it[3].

This begs two questions:

1) Maybe "freq_list" documentation needs to be clarified? Apparently, it has very
limited and unclear use.
2) wpa_supplicant could use a working way to enforce band selection. There's
clearly some need for it.

[1] https://lists.infradead.org/pipermail/hostap/2014-August/030761.html
[2] https://netplan.io/reference/#properties-for-device-type-wifis%3A
[3] https://bugs.launchpad.net/netplan/+bug/1944044